Prior art round balers generally have a bale forming chamber defined by an apron comprising an array of side-by-side belts, transverse slats extending between chains, a plurality of bale forming rolls or a combination of these various elements, e.g., bale forming rolls and side-by-side belts. The utilization of rolls in combination with belts is shown by way of example in the round baler of U. S. Pat. No. 5,044,272, issued Sep. 3, 1991 in the name of Richard E. Jennings.
During field operation, a pickup assembly picks up crop material, such as hay, from the ground and feeds it into a fixed or adjustable chamber where it is rolled up to form a compact cylindrical package of hay. While still inside the chamber the formed package is wrapped in its compact form by net, twine, or the like, prior to being ejected as a bale onto the ground for subsequent handling.
Round balers having chambers of the various configurations mentioned above commonly have a pickup with a set of tines that engage a windrow of crop material on the ground and lift it upwardly and then urge it rearwardly along a continuous path from the ground to the chamber. In certain configurations of pickups the tines disengage from the crop material and other feed assist means such as fingers engage the material to urge it rearwardly toward the chamber to assure continuous and smooth flow. Feed assist arrangements such as this are commonly referred to as stuffers in that they actually serve the purpose of stuffing crop material into the chamber. For example, U.S. Pat. No. 4,662,275, issued May 5, 1987 in the name of Werner Tertilt, shows a round baler having a conveyor between the pickup and the baling chamber. The conveyor comprise a series of prongs extending upwardly through accommodating slits in a metal tray. U.S. Pat. No. 4,579,052, issued Apr. 1, 1986 in the name of Siegfried Schaible discloses a similar system in which the prongs extend downwardly. U.S. Pat. No. 4,510,741, issued Apr. 16, 1985 in the name of Hallis D. Campbell, et al, shows another arrangement in which the pickup on a round baler does not feed material directly to the bale forming chamber. In this patent a standard pickup conveys crop material rearwardly to the nip between a pair of feed rollers which in turn continue it along its rearward path.
In some round balers, stub augers extend from opposing sides downstream from the pickup to reduce the width of the mat of crop material being fed to the chamber. In arrangement of this type it is common to provide the floor area between the pickup and the chamber with feed assist mechanisms. A good example of an arrangement of this type is shown on pages 2-1 through 2-3, taken from New Holland Operator's Manual No. 42064032 for round baler models 640, 650 and 660, issued in August, 1993. Because of the proximity of the stuffer fingers to the baling chamber it is important that random material is not permitted to build up in the vicinity of the chamber ingress when the fingers are retracted from the feed path. In the past, to guard against this undesirable buildup, a shield has been used, as shown in FIG. 2-7 on page 2-3. Unfortunately, under some crop conditions thorough stripping is not always achieved giving rise to accumulation on the shield which reduces effectiveness of the pickup by preventing smooth and uniform flow.